Spy Museum, China
The National Museum of Security Education in Nanjing, western China, is a museum dedicated to espionage and known to be accessible only to Chinese citizens.
Foreign visitors are not allowed here.
As the museum manager said, the exhibits (collections of small pistols, miniature cameras, secret hiding places and more) are not intended for overly impressionable foreigners.
In addition, museum visitors are strictly prohibited from photographing anything inside the institution.